Abstract: In a Fresnel lens which is made of a lens material whose refraction index is n, and focuses light beam from a light source at a specified radiation view angle ?, and has plural N pieces of circular lens surfaces arranged concentrically around a common optical axis, and plural circular rise surfaces arranged adjacent alternately between these lens surfaces, and two lens surfaces adjacent via at least one of the rise surfaces are concave surfaces, and tangent lines and at the intersecting point with the rise surfaces of the shape of a cross section passing through the optical axis of those lens surfaces intersect at the outside with respect to the optical axis, and when the angle formed between these tangent lines is defined as ?, a relational equation ???/(2 n N) stands.

Abstract: In a discriminating apparatus, a substrate portion of printed matter is irradiated with a light beam emitted from a light source, and the intensity of the light beam reflected from the substrate is detected by a photodetector. The discrimination as to whether the printed matter is the original or a reproduction is performed by a discriminating unit based on the contrast value in the intensity of the reflected light detected by the photodetector. Thus, the discriminating apparatus discriminates whether the printed matter is the original or a reproduction at high speed and also permits lowering the possibility of an erroneous discrimination.

Abstract: The present invention provides a step difference detection apparatus including an illumination section for emitting illumination light, an incident section for making the illumination light emitted by the illumination section be incident on a plurality of small illumination regions on an object carried in a predetermined carrier direction from different directions, an image sensing section for inputting an image of the regions on the object illuminated with the illumination light which is made to be incident by the incident section, and a detection section for detecting a step difference on the object on the basis of the image sensed by the image sensing section.

Abstract: A pattern detecting apparatus is provided with an illuminating device which separates a detected surface into a plurality of irradiation areas and irradiates an irradiation light to adjacent irradiation areas from different directions, an imaging device which overlaps and images the irradiation areas with a mask generating a moire, and an image processing device which detects a phase difference of a concentration change of the moire image in the irradiation areas when the moire image is obtained by the imaging device, thereby judging whether or not a pattern exists.

Abstract: An object of the present invention is to provide a display device which can realize a magnified image. A display device comprises a display panel having a predetermined effective display region PS, a display screen, and a magnifying optical system including a first inverting optical system constituted by a first lens array in which a plurality of first lenses corresponding to the display panel are arrayed and a second inverting optical system constituted by a second lens array in which a plurality of second lenses corresponding to the first lenses are arrayed. The magnifying optical system constitutes a plurality of channels for forming on the display screen a magnified erect image for a display image on the display panel through the corresponding first and second lenses. The magnifying optical system is constructed so as to form on the display screen an image of an image point on the display panel through at least three of the channels.

Abstract: The present invention provides a step difference detection apparatus including an illumination section for emitting illumination light, an incident section for making the illumination light emitted by the illumination section be incident on a plurality of small illumination regions on an object carried in a predetermined carrier direction from different directions, an image sensing section for inputting an image of the regions on the object illuminated with the illumination light which is made to be incident by the incident section, and a detection section for detecting a step difference on the object on the basis of the image sensed by the image sensing section.

Abstract: An optical element of this invention converts incident light having a predetermined shape and a predetermined intensity distribution into output light having a desired shape and a uniform intensity distribution. Furthermore, in an optical device of this invention, which has this optical element as a first optical element, a light source radiates a light beam having the predetermined beam shape and the predetermined intensity distribution, the first optical element shapes the beam shape of the incident light beam into one of rectangular, circular, and elliptic shapes having a uniform intensity distribution, and a second optical element gives a collimation to the incident shaped light beam.